In humans, the paranasal sinuses include several pairs of right and left sinus cavities, primarily the frontal, ethmoid, sphenoid and maxillary sinus cavities. Of these, the maxillary sinuses are the largest and the most common site for sinus infections.
The maxillary sinuses are located on either side of the nasal canal, below the eye socket and behind the cheekbone. Normally, each maxillary sinus has a natural ostium, which is an opening through which mucus drains from the sinus cavity into the nasal canal and through which air enters the sinus cavity. If the natural ostium of a maxillary sinus becomes obstructed due to microbial infection, chronic allergic inflammation or anatomical deformity (e.g., a deviated septum), the outflow of mucus and inflow of air may be impaired, thereby giving rise to a condition known as maxillary sinusitis. Less frequently, dental disease affecting the upper molar or bicuspid teeth, which are located just inferior to each maxillary sinus, may cause maxillary sinusitis.
In cases where maxillary sinusitis cannot be successfully treated with medical therapy (e.g., antibiotics, decongestants and steroid nasal sprays), surgery or catheter-based interventions are sometimes performed. The surgical approaches to treatment of maxillary sinusitis have included functional edoscopic sinus surgery (FESS), wherein an endoscope and various surgical instruments are inserted through the nostril and used to cut and/or remove bone and soft tissue in an effort to improve drainage and aeration of the maxillary sinus. In recent years, catheter-based approaches have been developed as alternatives to the cutting and removal of bone and soft tissue in the typical FESS procedure. In these catheter-based approaches, a dilator such as the balloon of a balloon catheter is maneuvered into the natural ostium of the maxillary sinus and used to dilate the natural ostium. Examples of such catheter-based procedures and related devices useable for treatment of maxillary sinusitis are described in U.S. Pat. Nos. 7,316,168; 7,500,971; 7,419,497; 7,462,175; and 7,410,480; and U.S. Patent Application Publication Nos. 2006/0004286, now U.S. Pat. No. 7,720,521; 2006/0063973; 2006/0210605, now U.S. Pat. No. 7,803,150; 2007/0129751, now U.S. Pat. 8,894,614; 2007/0135789, now U.S. Pat. No. 8,858,586; 2007/0167682; 2007/0208252; 2007/0208301, now U.S. Pat. No. 8,951,225; 2007/0293727, now U.S. Pat. No. 9,265,407; 2008/0097154, now U.S. Pat. No. 8,080,000; 2008/0097239, now U.S. Pat. No. 7,641,644; 2008/0097295, now U.S. Pat. No. 7,727,186; 2008/0097514, now U.S. Pat. No. 8,088,101; 2008/0097515, now U.S. Pat. No. 7,645,272; 2008/0097516, now U.S. Pat. No. 7,727,226; 2008/0103361, now U.S. Pat. No. 8,090,433; 2008/0103521; 2008/0119693, now U.S. Pat. No. 8,961,398; 2008/0125626, now U.S. Pat. No. 8,715,169; 2008/0154250, now U.S. Pat. No. 8,142,422; 2008/0195041, now U.S. Pat. No. 8,747,389; 2008/0228085; 2008/0234720, now U.S. Pat. No. 8,123,722; 2009/0187098, now U.S. Pat. No. 9,101,384; 2008/0275483; 2008/0281156, now U.S. Pat. No. 9,167,961; 2009/0030274; 2009/0093823, now U.S. Pat. No. 7,771,409 and 2009/0187089, the entire disclosures of which are expressly incorporated herein by reference.
As an alternative to, or in conjunction with, surgery or a catheter-based intervention of the type described above, various devices and methods have been proposed for delivering drugs or therapeutic agents into certain paranasal sinuses. For example, United States Patent Application Publication 2004/0116958A1 (Gopferich et al.), now U.S. Pat. No. 8,740,929, issued Jun. 3, 2014 describes tubular spacers formed of biodegradable or non-biodegradable polymers and loaded with an active substance, such as a corticosteroid or anti-proliferative agent. After surgery has been performed to create a fenestration in a frontal sinus, the space is placed in such fenestration, and the active substance then passes out of the spacer. Also, Tarasov D I, et al., “Application of Drugs Based on Polymers in the Treatment of Acute and Chronic Maxillary Sinusitis,” Vestn Otorinolaringol. 1978; 6:45-47 has reported the delivery of drugs directly into a maxillary sinus cavity for treatment of sinusitis. Additionally, Deutschmann R, et al., “A Contribution to the Topical Treatment of [Maxillary] Sinusitis Preliminary Communication,” Stomat. 1976; DDR26:585-92 describes the instillation of a water soluble gelatin mixed with the drug (i.e., Chloramphenicol) into the maxillary sinus cavity for treatment of maxillary sinusitis. Since this gelatin/drug preparation was relatively short acting, the authors reported that in order to achieve a therapeutic effect it should be instilled every 2 to 3 days. Devices and methods for sustained delivery of drugs into paranasal sinus cavities are also described in U.S. Pat. No. 3,948,254 (Zafferoni); U.S. Pat. No. 5,512,055 (Domb, et al.); U.S. Pat. No. 7,361,168 (Makower, et al.); U.S. Pat. No. 7,410,480 (Muni et al.); and U.S. Pat. No. 7,419,497 (Muni, et al.); and United States Patent Application Publication Nos.: 2003/0185872A2 (Kochinke), now U.S. Pat. No. 7,074,426; 2005/0245906A1 (Makower, et al.), now U.S. Pat. No. 7,361,168; 2005/0043706 (Eaton, et al.), now U.S. Pat. No. 7,544,192; U.S. 2006/0106361A1 (Muni, et al.), now U.S. Pat. No. 7,410,480; 2007/0005094 (Eaton, et al.), now U.S. Pat. No. 8,025,635; 2008/0015540 (Muni et al.), now U.S. Pat. No. 7,419,497; 2008/0287908 (Muni et al.), now U.S. Pat. No. 8,864,787; 2008/0319424 (Muni et al.); 2009/0028923 (Muni, et al.), now U.S. Pat. No. 8,388,642; 2009/0017090 (Arensdorf, et al.), now U.S. Pat. No. 8,535,707; 2009/0047326 (Eaton, et al.), now U.S. Pat. No. 7,951,132; 2009/0156980 (Eaton, et al.), now U.S. Pat. No. 8,858,974 and 2009/0227945 (Eaton, et al.), now U.S. Pat. No. 8,337,454, as well as PCT International Patent Application Publication WO 92/15286 (Shikani).
There remains a need for the development of new devices and methods capable of improving drainage and/or aeration of a maxillary sinus and/or delivering therapeutic substance(s) into a maxillary sinus.